A communication network may include any number of nodes interconnected by communication links. The networks may deliver electronic communications between two points by routing the communications over the links from one node to another node within the network. As the number of nodes in a network increases and as the number of communication paths available to each network node increases, the number of potential paths available for delivering any single communication likewise increases.
Routing is a key function for efficient and cost-effective operation and management of mobile cellular communication systems. Telecommunication networks, including terrestrial and satellite cellular systems, may share the following key characteristics (1) a dynamically changing network topology; (2) dynamically varying link capacities; and (3) time-varying traffic flow requirements.
For a given nodal communication infrastructure, the first two factors (network topology and link capacity) are predictable as a function of time. The third factor, the traffic offered to the network, is typically either based on marketing projections or on historical usage information. Whatever method is used, the time-varying traffic that must be carried between various pairs of nodes in the network is not accurately predictable. The problem of predicting traffic flow requirements is further complicated by unexpected events that cause temporary deviations in traffic demands. Such events will cause focused overload of traffic at unpredictable user locations in the system.
Networks often use techniques for specifying a route to follow when delivering a communication from a source node to a destination node. These techniques can be sophisticated and are often carried out by computer analysis based upon models of the entire network. The complexity of the route specification problem and the amount of intelligence and processing power required to solve the route specification problem can force at least a portion of the route determination problem to be solved "off-line" before the communications are actually delivered through the network nodes.
Selecting routes before communication delivery makes the network vulnerable to link failures. For example, when an off-line process evaluates the route determination problem, a particular link may be operational. Thus, the off-line process specifies the use of the particular link in various routes from various source nodes to various destination nodes. If this particular link then fails, all communications being delivered according to the off-line process specifications over the failed link fail to reach their intended destinations.
These conventional methods based on static routing techniques are suited for lightly utilized networks. For moderately or heavily utilized networks, the success of static routing depends on the accuracy of traffic forecasting methods used to define the routes. Moreover, these methods are sensitive to variations in traffic offered to the system. Accordingly, there is a significant need for a system and method which do not route communications based on static or preplanned routing techniques.